Re: [PATCH 3/3] Add marker_query service

Will apply, but I wonder why we start "instance" at 1 instead of 0... ?

* Jan Kiszka ([email protected]) wrote:
> Introduce marker_query(name, instance) to obtain a reference to a
> marker's __mark_marker_data structure. This information can be used to
> search for markers of a specific name and check the returned format
> string for consistency in more flexible ways or defer the check. So far
> consistency checks are done via a full string match on marker_set_probe
> invocation, now we can also apply checksum tests without having to know
> the string in advance in the context of marker_set_probe.
> 
> 
> Signed-off-by: Jan Kiszka <[email protected]>
> 
> ---
>  include/linux/marker.h |    1 +
>  kernel/module.c        |   47 +++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 48 insertions(+)
> 
> Index: linux-2.6.21.1/kernel/module.c
> ===================================================================
> --- linux-2.6.21.1.orig/kernel/module.c
> +++ linux-2.6.21.1/kernel/module.c
> @@ -448,6 +448,26 @@ static int marker_list_probe_range(marke
>  	return found;
>  }
>  
> +/* Looks up a marker by its name and instance number within the specificed
> + * range and returns the associated data structure. */
> +const struct __mark_marker_data *marker_query_range(const char *name,
> +	int instance,
> +	const struct __mark_marker *begin,
> +	const struct __mark_marker *end)
> +{
> +	const struct __mark_marker *iter;
> +	int found = 0;
> +
> +	for (iter = begin; iter < end; iter++) {
> +		if (strcmp(name, iter->mdata->name) != 0)
> +			continue;
> +
> +		if (found++ == instance)
> +			return iter->mdata;
> +	}
> +	return NULL;
> +}
> +
>  /* Calls _marker_set_probe_range for the core markers and modules markers.
>   * Marker enabling/disabling use the modlist_lock to synchronise. */
>  int _marker_set_probe(int flags, const char *name, const char *format,
> @@ -522,6 +542,33 @@ int marker_list_probe(marker_probe_func 
>  	return found;
>  }
>  EXPORT_SYMBOL_GPL(marker_list_probe);
> +
> +/* Looks up a marker by its name and instance number and returns the
> + * associated data structure. */
> +const struct __mark_marker_data *marker_query(const char *name, int instance)
> +{
> +	struct module *mod;
> +	const struct __mark_marker_data *mdata;
> +
> +	mutex_lock(&module_mutex);
> +	/* Core kernel markers */
> +	mdata = marker_query_range(name, instance,
> +			__start___markers, __stop___markers);
> +	if (!mdata) {
> +		/* Markers in modules. */
> +		list_for_each_entry(mod, &modules, list)
> +			if (!mod->taints) {
> +				mdata = marker_query_range(name, instance,
> +					mod->markers,
> +					mod->markers+mod->num_markers);
> +				if (mdata)
> +					break;
> +			}
> +	}
> +	mutex_unlock(&module_mutex);
> +	return mdata;
> +}
> +EXPORT_SYMBOL_GPL(marker_query);
>  #endif
>  
>  #ifdef CONFIG_SMP
> Index: linux-2.6.21.1/include/linux/marker.h
> ===================================================================
> --- linux-2.6.21.1.orig/include/linux/marker.h
> +++ linux-2.6.21.1/include/linux/marker.h
> @@ -116,6 +116,7 @@ extern int _marker_set_probe(int flags, 
>  
>  extern int marker_remove_probe(const char *name);
>  extern int marker_list_probe(marker_probe_func *probe);
> +const struct __mark_marker_data *marker_query(const char *name, int instance);
>  
>  #endif /* __KERNEL__ */
>  #endif
> 



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-- 
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68

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